In a motorized surgical stapling and cutting instrument it may be useful to control the velocity of a cutting member or to control the articulation velocity of an end effector. Velocity of a displacement member may be determined by measuring elapsed time at predetermined position intervals of the displacement member or measuring the position of the displacement member at predetermined time intervals. The control may be open loop or closed loop. Such measurements may be useful to evaluate tissue conditions such as tissue thickness and adjust the velocity of the cutting member during a firing stroke to account for the tissue conditions. Tissue thickness may be determined by comparing expected velocity of the cutting member to the actual velocity of the cutting member. In some situations, it may be useful to articulate the end effector at a constant articulation velocity. In other situations, it may be useful to drive the end effector at a different articulation velocity than a default articulation velocity at one or more regions within a sweep range of the end effector.
During use of a motorized surgical stapling and cutting instrument it is possible that the force to close the closure member and the rate of change of closure force experienced by the end effector may vary and the firing velocity may not be suitable. Therefore, it may be desirable to control the firing velocity of the cutting member or the firing member based on the closure force experienced by the end effector. It also may be desirable to measure the load experienced by the closure member and control the velocity or rate of the cutting member or the firing member based on decreasing load on the closure member.